Method of recovering metals from solutions.



UNITED STATES Patented May 10, 1904.,

PATENT OFFICE.

ISAAC ANDERSON, OF PRESCOTT, ARIZONA TERRITORY, ASSIGNOR OF ONE-HALF TOMICHAEL SOANLAN, OF VVHITEHILLS, ARIZONA TER- RITORY.

METHOD OF RECOVEHING METALS FROM SOLUTIONS-- SPECIFICATION forming partof Letters Patent No. 759,493, dated May 10, 1904.

Application filed August 8, 1903. Serial No. 168,832. (No specimens.)

To a whom it may concern.-

Be it known that LIsAAO ANDERSON, a citizen of the United States,residing at Prescott, in

the county of Yavapai and Territory of Arizona, have invented a new anduseful Method of Recovering Metals from Solutions, of which thefollowing is a specification.

This invention relates generally to recovering metals from solution, andmore particularly to a method for recovering metallic values fromso-called mineralized waters in which gold and silver and copper oriron, or both, are held in solution, the metals being in the form ofsalts of various kinds.

The Waters to which this method of recovering metallic values is appliedare waters such as How from mines containing what are generally known asbase oresthat is to say, gold and silver ores in which copper or iron,or both, are also present. Such waters also flow from stamp-mills andfrom pulp- .vats and, without treatment in the manner hereinafterdescribed, or in some other man nor to effect the precipitation of themetallic values contained therein, the mineralized waters from any ofthe sources above mentioned carry away with them considerable quantitiesof dissolved metals, which may be recovered in an economical andpractical manner.

Whenever mineralized waters contain gold and silver and iron or copper,or both, held in solution as salts of various acids, the metals presentin the water may be recovered by adding to the water a sufficientquantity of slaked or unslaked lime in finely-divided condition tocombine with the acids present in combination with the metals and withany free acid contained in the water. The quantity of the lime whichmust'be added will of course vary with the quantity of metallic saltsheld in solution by the water and the amount of free acid, if any, thatis also present, and the purity of the lime will also be a factor indetermining the quantity to be added. The lime may be added to themineralized water in any suitable apparatus, as in an ordinary flume,and the lime must be thoroughly mixed with the water by agitationbrought about by the action of mechanical force or by the action ofgravity in causing the water to flow down a flame. When lime has beenadded in suflicient quantity and the water, with the lime therein, hasbeen subjected to agitation sufiicient to bring about thorough mixing ofthe lime with the water, any gold and silver contained in the water willbe precipitated in solid form and may be recovered by filtration or byallowing the solids in the water to settle in a suitable receptacle inthe form of sludge, from which the water may be decanted or which may beremoved by any suitable means and treated by the cyanid process, bysmelting, or any other preferred method to recover the metals therefrom.

The method above outlined is primarily intended for use in recoveringfrom the Waste water of mines the metallic values contained therein; butit is equally suitable for use in treating the tailings fromstamp-batteries in which metals are held in solution by means of acids.When the tailings from batteries are treated, there will ordinarily be acertain amount of free acid to be overcome by the lime in addition tothe acid by which the metals are held in solution, and suflicient limeto combine with the free acid, as well as with any combined with themetal, must be added.

When mineralized waters containing gold and silver in solution alsocontain salts of copper or iron, or both, the addition of lime alone tothe waters and the thorough agitation of the mixture of water and limewill be sufiicient to precipitate the metals; but in case the Waters donot contain copper or iron in addi' tion to the gold and silver it willbe desirable to add either copper or iron, or both, to the solutionbefore adding the lime. When the base metals are added to the solutioncontaining gold and silver and lime afterward added, the action is thesame as if the lime had been added to a solution containing all of themetals in the beginning.

I have found that lime is useful not only in recovering metallic valuesfrom mineral waters, but that it may be used to advantage with ores fromwhich the metals are to be separated and recovered by amalgamationWhenever the ores to be so treated contain acids which will affect thebattery-screens or by acting upon the surface of the mercury arranged inthe sluices for amalgamation the mercury will be coated with a thin filmof some salt of mercury, which will lessen its activity as anamalgamating agent, and when it is desired to overcome the action of theacids in such ores upon the battery-screens and upon the surface of themercury the lime is to be introduced with the ore into the batteries.

I am aware that it has been proposed to use lime in precipitating goldfrom sea-water, in which it is said to be present in the form of theiodid; but so far as I am aware lime has never been used under thecircumstances set forth in the foregoing paragraphs to precipitate goldand silver from mineralized waters in which gold and silver are held insolution in the presence of iron or copper, or both; nor has any onebefore my discovery, so far as I am aware, used lime withstamp-batteries along with the ore treated therein to prevent action ofacids present in the ore upon the battery-screens and upon the mercuryused for amalgamating the metals contained in the ore.

, Having thus described the nature and use of my invention, what I claimas new, and desire to secure by Letters Patent, is-

1. The method of recovering precious metals from solutions, consistingin treating the solution with lime in the presence of baser metals.

2. The method of recovering gold and silver from solutions, consistingin treating the somy own l have hereto affixed my signature inwitnesses;

ISAAC ANDERSON.

Witnesses:

J. 0. WILSON, M. MoGE'rmoK.

the presence of two

